One of the problems associated with the use of a fuel pump with a commutator-type motor submerged in diesel or other forms of light oil is skating of the commutator brushes over the surface of the commutator. Fluid forms a film over the face of the commutator and becomes trapped between the brush and the commutator face as the commutator rotates. The fluid film elevates the brush away from the commutator face and the result is heavy arcing. Arcing results in increased brush wear.